Geoffroy Saint-Hilaire, Etienne (1772–1844)

French zoologist who performed some of the earliest embryological experiments on chicks. He tried to halt the development of a chick embryo at the stage of a fish in order to demonstrate that evolutionary stages of development are recapitulated in the embryo.

Early on in his scientific career he worked with Georges Cuvier, but they parted company and became rivals. In 1825 Geoffroy Saint-Hilaire developed an interest in palaeontology and he identified Cuvier's fossil ‘crocodile’ as a Teleosarus.

Saint-Hilaire was born in Etampes in France. Although the youngest of 14 children, he received special tuition from the Abbé de Tressan which ensured that he was a canon by the time he was 15 years old. He had a promising future in the church, but when the French Revolution started he left the church in order to study first law and then medicine. In 1792 he met several of the most eminent scientists of the time at the Collége du Cardinal Lemoine in Paris. He was made a professor at the Museum d'Histoire Naturelle when he was 21. From 1798 until 1801 he served as a scientist on Napoleon Bonaparte's Egyptian campaign and wrote Description de L'Egypte par la Commission des Sciences, describing his discoveries.